


Knot me Up.

by Skydiver_Tomyo



Category: The Avengers (2012)
Genre: Alpha/Omega, Aniuman, First Time, Half human half animal, Knotting, M/M, Mentioning of Clint/Phil, Mpreg, The plot kinda disappeared somewhere.., Tony going into heat, but really, is kinda hot, it's just PwP
Language: English
Status: Completed
Published: 2013-05-15
Updated: 2013-05-15
Packaged: 2017-12-11 23:06:33
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 7,089
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/804283
Author URL: https://archiveofourown.org/users/Skydiver_Tomyo/pseuds/Skydiver_Tomyo
Summary: <blockquote class="userstuff">
              <p>Tony goes into heat, and as an Omega aniuman, that's a bit of a worry, except, Steve is an Alpha aniuman, even if he isn't aware of it.. and they are compatible.<br/>Smut ensues and Stony happens!</p>
            </blockquote>





	Knot me Up.

**Author's Note:**

> Wrote this while mindlessly fangirling over Stony alpha/omega stories :P  
> Well, who doesn't like porn?
> 
> Alternate story, altered with the fact that some people are Aniuman, not humans.  
> Aniuman is half human, half animal..

A typical day in the Avengers Tower was as their usual start. Getting up at all kinds of hours, beginning with Steve heading out for a jog at 6 am sharp and eating when returning, just around the time Clint appears through the air vents, around 7 am before disappearing off into the vents again after eating. Tony constantly nags him about that, but let's him anyway. Natasha comes in around 9 am, sitting there for a good while and eating, joined by Bruce around 9.30 am. Thor comes, half naked into the kitchen around 11 am, not awake until he has had at least one cup of coffee and one poptart. Lastly, if not at all, is Tony, who'd stumble in around 2 pm, his brain not even functioning yet. Or he'd come in around 3.30 pm, grabbing a cup of coffee and chat with whoever was there, in that case, having staying in the workshop all night. By that time, the rest was either eating lunch or in Steve's case, dinner.

Then the day moves on to a possible mission to kick some super villains ass, again, if not, they gather in the movie room and watch something random, though Tony rarely showed up, he did try when he could. The rest staying there till around 10 pm when Steve goes to bed, followed by Bruce a few minutes later. Natasha and Clint will go to bed around 12 pm and Tony, who is either not there, or already asleep, in which case, he stays there throughout the night, snoring away to wake up around 4 am and goes either to his workshop or his room.

Very boring in the length, but they didn't mind, even if they weren't all human. It wasn't a common knowledge, but it was known between the team members who decided to tell the rest that they were an aniuman, a cross specie between human and animal, though divided into three categories, Alpha, Omega and Beta. It was pretty obvious what Clint was, an Omega hawk, belonging rightfully to Coulson by their bond as mates.

Sometimes they'd find feathers littered about in the towers, chairs and couches, and Tony would constantly bitch about feathers in the air vents and yell at the archer to clean up after himself. Though Tony never actually seemed to mind in the end. Natasha, an Alpha leopard, wasn't much different from usual, but she had sharp nails to go with her attitude of a large feline and no one messed with her when she was in the mood for a kill, which she often was due to her Alpha nature. Bruce, the good typical large house dog, a Beta Labrador that goes into aggressive, rabid Alpha wolf when hulking out, though usually he had large, brown, fluffy ears that Tony just loves to pull whenever Bruce is brave enough to show his form, which is very rare. Thor, obviously, is a demigod, that explains it all. Nothing else is known about that last two though, though the rest knew that neither Steve, or Tony was human, they just hadn't told them yet, even if they aren't all to aware themselves from how they act.

* * *

 

It doesn't come to Steve as a surprise when he find Tony in his workshop, but not as engrossed with his work as usual. He's been there a few days now, which doesn't worry the team too much really. The moment Steve enters the room Tony goes rigid, sniffing the air like an animal before turning away completely.

“What's up cap?” he sounds oddly forced. Steve let it go in favor of his task at hand “dinner, you weren't at breakfast, nor lunch-” he stopped when Tony whirled around in his chair, easily, and almost feline in movement moves out of the chair, grabs the plate with whatever Steve cooked for them all was in. It's down within a few minutes, with Tony sitting on a nearby work desk using a finger to literary clean the plate. Then he looks at Steve with the kind of hungry look only a dog could muster, holding out the plate towards him.

“More?” he asked, sounding far to innocent and Steve is nods, keeping his face straight.

“Come up then.” but Tony shakes his head. Something is odd about him today. “Busy..” he just mutters and goes back to his work. As he passes Steve, the captain catches a new scent from the man, sweet, inviting, wanting. Steve blushes before fleeing the room, hoping Tony didn't see the shameful look Steve had on his face. He get's Bruce to go back with a second round of food to Tony. Natasha sit down at the table as he returns.

“To busy to eat?” she asked. Steve shakes his head. “No, didn't seem so, he ate it all within a few minutes and asked for seconds after nearly licking the plate clean..” he said. Natasha stared back before she groaned.

“Of all the times of the year-” she muttered to herself. “What?” Steve asked. Natasha sighed.

“It's possible he is an aniuman, like us, or rather, like me, and he might be going into heat, which our kind does when finding it necessary to breed.” and Steve's mouth falls, as does Clint's, making the cereal pour out of his mouth making him look really ridiculous. “Okay, thanks, too much info, thanks Tasha.. heading out!” the hawk is quick into the air vents again.

“Well, if he is in heat, Dr. Banner will notice..” a short break “you sent him down?” Natasha asked. “Didn't want to go down again.” Steve muttered. The spy just frowned.

“You smelled something didn't you?” she asked. Just then, Bruce came in, looking oddly hazy.

“Heat?” Natasha asked, and Bruce's eyes cleared “yes, definitely heat, and he hasn't bonded so he's without a mate..” “you figured out his position?” Natasha asks and Steve made a funny noise, which the other two ignored. “Omega, without a doubt.” and Natasha groans. “Great, just what we need.. Tony in rut and without anyone to keep him in check, if we at least had someone who could just knot him up.” she complained. Steve just stared at them before he sighed.

“But, what did you mean.. by smell?” and Bruce's eyes went to him “you.. smelled his scent?” he asked. Steve frowned, thinking about it. “Well, it was him the smell came from so, I guess.. yes..” Steve agreed.

“Sweet? Wanton?” Bruce asked, looking deadly serious. Steve nodded. “Exactly.. just, more.. really, it was really powerful, like he'd showered in a perfume..” he stated.

“Great.. just great, you, go down to Tony, right now!” Natasha simply said. Steve frowned.

“Why?” he asked. Natasha raised an eyebrow. “No questions asked, GO!” she snapped and he stood up, fleeing the room in fear of the feline. Bruce and Natasha watched the captain disappear.

“Of all people, and he doesn't even seem aware..” Natasha groaned. “Tony knows at least what he is, and he seems aware of what his scent does to Rogers.” Bruce explained, sitting down.

“Nothing we can do about it.” Natasha said.

“I do wonder though..” she began and Bruce looked at her. “What?” he asked. “What kind of specie he is, he doesn't smell like your typical animal, I can't quite.. place my tongue on it, some times I smell dog from him, other times he smells like Clint.” she said.

“Well, we'll probably get to know later.” and Natasha smirked at the scientist. “Indeed we will.” and during all this time, Thor had managed to eat the rest of the food on the table and was pleasantly relaxing in his chair before he fled, chased by Natasha for stealing her portion too.

* * *

 

And Steve found Tony on the couch in the workshop where he usually sat, drawing art while talking with Tony. Said genius was on it, scratching the fabric with eagerness while rolling lazily about in the pillows. Steve groaned. He could see the beads of sweat on the genius' forehead and knew the man wasn't comfortable, but he was holding back.

“Tony..” he called. Tony didn't seem to hear him, just continued to scratch. And now he was purring too, putting his nose into the pillows. Then he dragged long nails against the couch and Steve groaned. “Tony! Stop that!” Steve snapped. Tony perked up, his eyes following him intensely. Those are the times Steve have to take a double look, when Tony's eyes changed slightly, looking more feline. Steve swallows.

There's no doubt that Tony is anything but human. The scent is stronger, and it's still intensifying as they stare at each other. Steve groans again before he sighs. Tony just snickers.

“Is that an order?” he teases and Steve swears Tony is purring at the end.

“Yes, now stop it!” Steve says and Tony pouts, then he smirks “um, no, it's my couch, so mine to scratch.” and Steve snaps. He walks over and grabs Tony by his wrist, dragging him up and gives an outright yowl when Tony's scent catches in his nose. Tony stares back. Brown eyes, deep, feline and amused. Blue eyes, canine and hazy. Tony gives a chuckle.

“Now now cap, be a good boy and try not to bite my head off.” he said and Steve stares back.

“I'm not some dog!” he snaps and Tony laughs “of course you are.. or at least some sort of four footed animal, or else my scent wouldn't have made you so crazy.” he said and stretches upward, closing the distance and Steve's eyes grow hazy again.

He swallows heavily, heat rising to his cheeks. The scent radiating from Tony making his dizzy with need.

“You are affected by my scent, humans doesn't notice the scent as more than feline pheromones, but you know, you can smell it and it's affecting you a lot more than normal, so you can't be human.. actually.. if I wasn't completely wron-” he was cut of by Steve.

“W-what? Of course I'm human.” he protests and Tony raises an eyebrow. “Then why are you growling?” he teased and Steve slaps a hand over his mouth as he realizes that yes, he is actually growling slightly. Not the 'I'm gonna bite your head off'growl, but rather, 'I'm in charge here, you better submit'growl. Tony just steps of the couch and steps into Steve's personal space, smirking and dragging a long, slender finger down the captain's chest. The man growls again and Tony's eyes changes again, just barely, but Steve sees it. Submission.

“Then what are you Tony?” he fired back. Tony seems to think about it, then he smiles.

“Why don't you find that one out yourself cap?” he teases and pulls away, escaping around captain and literally saunters off towards his room. Steve turns, seeing a black tail swaying back and forth behind Tony, well, on Tony's behind actually. As he passes the doorstep to the hall, Tony looks over his shoulders and Steve can smell the pheromones in the air, leaving a trail and it sends his senses flying. So, he stalks the man to his room and closes the door, locking it.

“Aniuman.. I figured as much, but what? Feline, yes, specie? I can't.. figure it out, and it's driving me mad, your smell..” he whispers and Tony's ears, those black, perked, fury ears twitch. The man is standing with his back to him, but Steve could just about see his smirk anyway.

“Only a fellow aniuman can smell the scent of another, so yes, yes you are one too, and you should be able to figure out my specie just from my color, really cap, for an Alpha, you really suck.” Tony said, turning and Steve is loosing it all. Tony's eyes are completely feline. His pupils are thin lines, widening slightly at the difference in light. Steve growls and Tony's ears moves back.

“You are a lot more submissive than I thought you would be, or ever thought you'd act.” Steve muttered, crossing the room, easily trapping the feline in his arms.

Tony snickered “I'm an Omega, it's expected to be submissive, and you are more accepting about this whole deal that I thought, I never thought I'd catch you though, was waiting for Bruce, or even Romanov to kick down my door and have me on the floor, even if I know that Bruce is a beta and Romanov is, strictly speaking, not interested in my scent as an Omega.” Tony said. Steve's eyebrows flew up towards the sky somewhere while he worked in the information.

“Romanov is a very strong woman indeed.” he said “but of the same specie as me, Bruce is a dog.” “I know..” Steve muttered. “He isn't much of a dominant dog, unlike you.. unless he hulks out, Hulk is Alpha and Bruce is Beta.” Tony traces a finger down Steve's chest while saying so, and Steve has to take an extra breath. Then Tony's lips are on his, pushing, licking, nipping. Steve growls, pulling Tony away by his hair long enough to look at the genius in aniuman form. His pupils are widened insanely, like opening a door to his soul and Steve knows just what the genius wants and groans.

“You're in heat.. are you even aware of what you're doing?” he asks. “It would explain the scent wouldn't it?” Tony asked sarcastically, shrugging. Tony slips a hand down and grabs him between his legs. Steve losses all coherent thought for a second before he growls and pushes Tony down onto the bed, getting on top.

“And so are you, my scent matches yours, so I'm guessing there's a lot more to this than both of us knows.” Tony said, grinning when Steve stops, blinking in confusion.

“Me? I.. am?” he hadn't noticed, considering he didn't even know. Tony reaches up, tugging at something and Steve growls at this new feeling.

“Hm, I can already specify your specie, you're without a doubt.. can- holy shit..” Steve stops, frowning.

“What?” he asked. Tony holds up a large, brown and blonde feather. “You are special Rogers.. canine and bird, I've never meet a cross between two species before, no matter rang.” Tony muttered, grinning. Steve frowns, then he gasps, the smell intensifying again. “Good God Tony.” and he literally rips Tony's clothes off of his body.

Tony stares up at him, and then starts to purr and Steve losses it completely, growling deep from his throat. Tony's ears moves back in submission. Pressing against the smaller man, he easily works out the knots of pleasure on Tony's body, following instinct. The feline man moaned, or maybe he meow'd, who'd ever know anyway? Steve licked up his neck, finding a spot right under his chin, where he could feel his heartbeats thumping frantically.

Tony gave a loud, drawn out moan at that one. Steve reached out, nibbling Tony's human ears and Tony's entire body shook as he gave something stuck between a squeak and a moan.

“Steve, please..” Tony moans and Steve's eyes met the feline. Clothes can't be shed fast enough.

“Tell me Tony, tell me how you want it.” Steve surprises himself by saying so. He'd never do this with anyone on whim, much less with the one and only Tony Stark. Tony just whined, his hands trying to reach over to Steve, who grabs his hands, pushing them down against the bed. Tony's eyes are cloudy, wide and nearly black with lust.

Something deep within him roared at the closeness, demanding more. Steve didn't know what it was, so he figured it was the Alpha in him commanding him to take Tony, knot and breed him, and then bond.

“I need you.. fuck me.. please..” Tony pleads. Steve finds himself smirking. “How much?” he asks, no wait, he's teasing. Tony's ears move back again before he pleads. “I need you so much it hurts, please.. please Steve, fuck me!” Steve releases the mans hands to move his hands down his body. He grabbed Tony's cock, pumping and stroking hard. Tony cried out.

“Please.. I need you.. I want you to knot me, fill me up..” he pleads. Steve just continued to stoke the smaller man's dick. Steve moved his other hand down further, using a knee to push Tony's thigh's apart. Tony moans and Steve presses a finger against the tight entrance.

Steve stops immediately after. In fact, he had never done this before, and yet he knew what to do. His instincts telling him what to do, so Steve looked about. No lube and Tony seems to know. “Hey, Goldilocks, I'm an aniuman, you think I wouldn't have natural slick?” he teased and Steve felt a flush rise to his face. Steve looked down, and Tony was right, he was already wet.

“God, Tony..” Steve groaned. He was left in nothing but his boxer by the time the clothes had finally gone and even his underwear seemed awfully tight. Steve released Tony's cock to work his boxer down. Any other situation and Steve probably wouldn't have ever done this, not at least without having dated Tony for at least a few weeks, but his instincts pushed him forward instead of listening to his human brain.

Steve moved the hand down right away, once again pressing a finger against Tony's slick hole. Tony moaned in anticipation. “Please.. oh, Steve.” he whispered, trying to move closer to the finger. Steve groaned at the sight of Tony moving back against his finger, wanting him so badly. Steve pushed the finger against Tony's entrance, feeling the muscle give away for him. Tony moaned.

“Mm, yes.. Steve.” the feline moaned again and Steve pushed the finger further in. It was hot, soft and making Tony go completely wild. The man's back arched as he pushed back against the finger, pleasure shooting up through his spine, which was visible in his darkened eyes.

Steve pushed the finger all the way in and found a spot, soft and so ready. But Steve kept himself from just fucking Tony so hard and fast that he wouldn't be able to take a single step tomorrow. He didn't want to hurt him. The super soldier pressed a second finger against Tony, who made some sort of sound that was full of pleasure and lust. “Please.. Steve..” Tony moaned, his ears laying flat against his head.

Steve leans down, kissing, biting and sucking down Tony's torso, giving more and more attention to each of Tony' nipples, causing Tony to moan loud and arch up against him. Steve pushed a third finger against Tony's already stretched hole and pushed in, already getting inpatient and more than ready to knot up Tony, despite not knowing how or what that even meant, but then again, Steve was a fast learner and caught on fast to most of the things thrown at him. The smaller man arched, biting his bottom lip hard and closing his eyes tightly. Steve slowed a little, but continued.

“It's going to be okay.. just relax.” he whispered “relax..” then he kissed down Tony's abs. Tony groaned, his eyes barely opening to show completely black eyes, full of lust and a tiny bit of pain. “Steve..” something clicked in Steve's head and he thrust his fingers sharply into Tony. Right up into his prostate. Tony hissed and moaned, his body shaking hard from the pleasure and so Steve continues that, occasionally stretching Tony by spreading his fingers.

Steve felt his own cock twitch, knot widening, as Tony moaned again, purring softly and he pulled away, watching as Tony's body went slack on the bed, giving a whimper “please.. more..” he whined. Steve pressed closer, giving Tony some indication about what's about to come. The feline just purred and pushed back against him, their lower half's meeting, making both moan. Tony arched his back and spread his thigh's further apart, showing his interest. His tail wrapped around his left thigh, moving out of the way for Steve and the soldier groaned at the sight.

“God.. I want to.. to..” he didn't know what he wanted to do, but he knew it had to do with the knot, Tony and sex. Tony gave a whimper “Steve.. please, God, please, knot.. knot me..” and Steve groaned. He pressed himself against Tony, feeling his tense and then relax against him.

“Steve..” Tony murmured, sounding so sure despite the lust so evident in his eyes. If Tony could get drunk on lust, he would have had to go in for detox ten minutes ago. Steve had to steady himself as he pushed against him again, pressing his cock up against Tony's stretched hole. Tony gave a purr and Steve pressed harder, slowly pushing past the muscles. Tony whimpered and tensed. Because, without the need to even see, Tony had known that Steve was well endowed, and he most certainly knew, or rather, felt that now. Steve leaned down.

“Relax..” he whispered, kissing the other man, softly biting his bottom lip before thrusting his tongue into Tony's mouth, making the genius arch and relax enough for Steve to go halfway in. Slowly, but surely Steve felt his control drain like a tap opened to full force. He grabbed Tony's thighs, further opening him up for him before he pushed harder, fully seated within Tony in just a few seconds, all except the knot that is. Tony's eyes rolled into the back of his head and his fingers grabbing the sheets hard. Steve leaned down, gracing his teeth across one of Tony's nipples, making the smaller man jerk and keen. The soldier just growled, making Tony's ears flush back to his head again, his eyes wide and obediently focused on Steve and Steve alone.

“Mine.” Steve growled and Tony made a non-comical noise and bared his teeth at the super soldier. There was an ongoing battle in Tony's eyes that Steve recognized. Tony wasn't comfortable with this little control, without some sort of say in this. Tony hissed slightly.

“Earn it..” he grunted and Steve thrust sharply into Tony, feeling his own knot growing -not yet locking them if he thrust all the way inside- but growing enough to make Tony sputter some syllables that wasn't strictly human. Steve growled again, baring his teeth before pushing his face into the crock of Tony's neck, biting down on the jugular.

“Oh.. oh God!” Tony moaned, once again obediently letting Steve use his body. Suddenly Steve pulled out and Tony gave a whine in protest.

“On your knees..” Steve commanded hoarsely and Tony scrambled to get up in a sudden, clumsy and fast pace that made him look comically adorable. Tony put his ass up in the air, while his torso rested on his elbows, and the captain took a good grip, spreading his ass to look at him. Tony gave another whine at this, but otherwise stayed still. Steve's hands wound their way down to Tony's hips, grabbing him in a bruising hold and the feline gave a keen.

“Steve..” he moaned, wriggling his hips. Steve stood up on his knees, driving his cock against Tony's entrance, pushing and easily slipping all the way up to the knot. The genius arched and moaned loudly, stretched and obviously happy with that.

“M-more..” Tony managed, but Steve's hold on him tightened and Tony tensed. “Mine..” Steve growled, with an underlying demand, 'I'll be the one doing the ordering' and Tony hissed. Steve stared down at the bonding glands just below Tony's hairline and was tempted to kiss him there, to bond with him, but shoved that thought away to concentrate on his task at hand. Besides, he didn't know if Tony wanted to bond or if this was a heat-spurred moment. He pulled out slowly before Steve stilled. How had he even known that there was bonding glans there? How had he known about the bond? Was these feelings, this knowledge some underlying instinct from his birth? And why Tony? What was so special about him? Sure, he was a brilliant genius, one of the biggest billionaires on Earth, and one of the biggest playboys around. But what else? Steve shook his head, smiling softly. Kind, though arrogant. Tony was a joker, a man who took great joy in tricks and engineering. He was a tad to into alcohol and sacrificing himself in battle. Damn bastard knew that he was loved for it. Steve grinned and leaned down slightly.

“Tony..” he moaned before he snapped his hips forward, burying himself deep into Tony and pushing into him all the way up to his knot. Tony's head jerked up, a loud moan escaping him. Steve groaned, suddenly losing all control of his hips. Tony let out something resembling a scream as Steve's pace increased by tenfold, his hands going down to Tony's shoulders, keeping him in place.

“Mine.” Steve growled, and this time, Tony keened with submission “yours! Oh God, Steve, I'm yours!” he cried out, meeting Steve's harsh thrusts. Steve reached down, harshly biting Tony's neck close to the bonding glands and Tony jerked. “Oh God.. please..” he moaned and Steve had to take in a sharp breath.

“Please what?” he muttered, not slowing down his pace with the other man.

“I.. need.. you.. bo- bond with me..” Tony managed. “Likewise..” Steve muttered and drove himself harder and harder into Tony as he felt the knot swell. He knew he was close and wanted to give Tony more, so he sucked on top of the bonding glands while thrusting all the way into Tony, pushing the knot in as well. Tony suddenly jerked forward, a keen escaping him and he came.

“Y-yes..” Tony garbled. Steve groaned and stopped, deep within Tony.

“Oh.. oh..” Tony keened as Steve continued to suck and bite on the glands. Suddenly his mind was filled with emotions. Lust, happiness and love washed over him with such strength Steve could only groan before he came, filling up Tony, and he probably came for about five minutes. It was tight, warm and so damn good to be locked with Tony this way. Steve let out a satisfied sigh and he slowly pulled away, but he couldn't pull his lower half away.

“Uh.. Tony, I'm kind of.. stuck..” he said, trying to move and Tony let out a pained cry. “N-no.. not yet.. the knot..” and Steve had to look closer. Of course, he hit himself on the forehead. The knot. He sighed and smiled before gently tipping them over so he could spoon Tony.

“It's okay..” he murmured. Tony let out a tiny moan and clenched around him. “Mm.. stay just like that..” he moaned.

“Yeah, I'm not moving.” Steve agreed, kissing up and down Tony's neck. They laid like that for another ten minutes and Steve was -not surprisingly- still hard.

“Uh, Tony, how long does.. knotting last?” he asked. Tony turned his head sleepily “around fifteen minutes I guess, that's how it is with most Alpha's.. why?” he asked. Steve could feel the emotions wash over him again. Insecurity, hesitation.

“Nothing, I just wondered when I can continue to fuck you.” and Tony's face was alight with a blush. Steve grinned when Tony nodded “just wait.. till the knot.. goes down..” he mumbled and Steve smiled.

“I can.. feel you..” he mumbled and Tony moaned “thanks, I fucking feel you too, in more than.. one way.” he answered and to that, Steve blushed. “There's.. no need to feel insecure..” he mumbled, causing Tony's head to jerk around and Steve winced at the angle Tony's head was in. There was a bit of anger in his eyes and he could feel the other man's emotions, but they weren't anger, they were embarrassment. So obviously, Tony didn't like to have someone know how he felt all the time. Steve pressed a short kiss against his cheek.

“Sorry, I didn't mean to, I should have know you don't like people pinching and prodding your heart.” but Tony shook his head “it's.. fine, I guess.. if it's you..” he muttered before he turned back so that the weird angle on his neck wouldn't give him cramps.

“I didn't know.. we were compatible..” Tony suddenly said “me neither.. not that I actually knew much anyway.” Steve muttered and Tony let out a weak laugh. The minutes slowly passed and Steve waited patiently for the knot to disappear. Tony, on the other hand, wasn't as patient. He pressed backwards into Steve and rolled his hips, causing a moan to escape both men.

“Gh.. Tony..” Steve grunted, grasping the mans hip with one hand to stop him from moving “mm, I want you.” Tony moaned.

Steve's free hand grabbed the black tail that was tucked between them, causing Tony's body to jerk forward and a cry of pleasure to escape him. Tony's cock twitched in interest and hardened, apparently having gotten over it's refractory period. Steve dragged his fingers up and down the base of the black tail and the genius was soon a moaning, mewling mess writhing against his cock, his own now fully hard and weeping from the overload of pleasure. Steve could feel the pleasure riding across their bond, it was strong, heavy and it made his body tingle with both interest and lust.

“I heard.. that a cat, it's tail's base is.. really sensitive.” he murmured against Tony's ear, continuing to give the tail it's attention. Tony whimpered and nodded furiously “y-yes..” Steve just smiled before he pressed his lips against the other man's neck, marking him with harsh sucks and gentle bites. Tony arched his back, hips pushing against Steve, but Steve didn't move, he only continued to stroke other smaller man's tail. Then his body fell a little away from Tony and Steve looked down to see that the knot had deflated enough for him to slip out and he grinned, using his hand on Tony tail to move him and his other hand on his hip.

In quick succession, Steve got Tony up on all fours again, the smaller man already shaking. Come was already dribbling from Tony's hole, but Steve pushed it back in with his thumb, the rest of his fingers resting against his tail. Tony moaned, moving against the single digit. Steve moved and quickly thrust into Tony, causing the man to jerk forward with a cry and then move backwards to meet the insane thrusts of his mate.

“S-Steve..” Tony's body jerked at the movement of Steve's cock and his hands on his tail and hip. Steve moved a hand down, pushing his thumb into Tony, alongside his cock. Tony arched, crying out “oh.. yes, yes yes yesyesyesyesyes!” he chanted, his arms trembling and threatening to break under him and the constant movement. The bed slammed into the wall continuity as Steve fastened the pace and if possible, strengthened it too. The soldier groaned, knot swelling and body stiffening. Tony met his thrusts the best he could and making noises that pushed Steve further towards the edge. He pulled out his thumb before both his hands went for Tony's waist, grabbing his in a tight, bruising hold.

“STEVE!” Tony literally screamed as Steve thrust into him as hard as he could and stopped, pressed against Tony's prostate as his knot locked them together. Steve leaned down, resting his chest against Tony's back, trying to get back his breath, which wasn't really hard considering his super soldier body. Tony on the other hand, was still moaning and panting like he'd run marathon, though he probably killed more calories this way than running around on a field.

“Tony.. you haven't come?” Steve asked, moving a hand down to Tony's cock and the man groaned “n-no.. not yet.. please.. not yet..” Steve could feel the focus Tony so clearly held on to. Steve raised an eyebrow before he kissed the back of Tony's neck while moving the hand up Tony's chest to his throat and rubbing under his jaw. “Come.” he whispered. Tony groaned loudly and then he jerked and shouted, coming across the sheets. The sudden tightness and the spasm inside Tony was more than enough to jerk an orgasm out of Steve as well and he came hard, filling up Tony once more. They collapsed then, with Tony pressed underneath Steve, who tried, but couldn't quite move.

“Cheater..” Tony breathed out, sounding grumpy, but Steve could only sense amusement from him so he sent amusement back. Steve pressed his lips against the bonding glans on the back of Tony's neck “I'm..” his words fell silent, but he knew Tony knew so he didn't try to finish the sentence anyway. There was a low, wheezing chuckle from underneath him and he instinctively moved to the side, pulling Tony with him so that he could breath better.

“Thanks, hero in shining armor.” Tony murmured. Steve chuckled “I'm a hero, but I don't have a shining armor.. isn't that you?” he asked and Tony laughed “maybe I am..” he murmured, but Steve growled, causing Tony's ears to go flat again. “You are a hero Tony, more than any of us.. and God.. sleep, please..” he yawned, causing Tony to chuckle “you're tired? Already?” his hips moved against Steve, causing the soldier to groan and jerk against him.

“Tony, you've come twice!” Steve complained. “So?” Tony asked, turned his head slightly “I'm not that old.. besides, I've never.. um..” he seemed uncomfortable now and Steve soothed him by stroking his stomach with his free hand, causing the genius to relax in his hold. Steve lay there for a good five minutes before his brain finally did the equations.

“W-wait! Y-you were a.. a..” Steve seemed at a loss of words. Tony slowly nodded.

“And yet.. God, Tony, you should've-” Steve stopped when Tony hissed.

“I'm not made of glass Steve, I'm fully capable of making my own decision, and I am quite fine with saving myself for something like this, even I'm not that filthy that I will sleep around with other aniumans or during heat.” Tony grumbled. Steve nodded slowly. “I didn't mean to.. make you angry, and I know you aren't, it's just.. precautions, and I'm honored.. I am..” Steve smiled when he felt shock across their bond. Tony didn't seem to have expected that at all and it made the blonde chuckle to himself.

Tony moved back then, getting another jerk from Steve “Tony, God.. you're still.. in heat?” he asked. Tony groaned “my last heat lasted two days Steve..” and Steve gave a whimper “we need to sleep, and eat.” he argued. Tony chuckled.

“I know that smart ass, really, you think I haven't made everyone aware of this.. besides, there are usually.. breaks during the heat that, well, I have one now, it'll give us time to sleep, eat, shower, play, whatever the heck it is couplings do during heat.” Tony answered. Steve pressed his lips against Tony's skin again, breathing in his scent and marking him even more. After a while, Steve let himself go along the questions of the bond

“Are you.. fine with it? I mean, I am, but..” Steve's words fell short of himself. “Yes, relax soldier, yes, you think I wouldn't have protested if I didn't want a bond? Tony asked and Steve chuckled “good point.. and Tony, sleep, please, even I have to get new energy..” Steve muttered. The knot had already deflated, but he didn't care with moving away. The need to protect and stay as humanly possible to Tony was high enough to cause a high alarm if he moved any further away at the moment. Tony yawned.

“M'kay.. you'll probably wake up when the heat comes back online..” Tony murmured. Steve managed to wriggle the sheets away from underneath them and then somehow tuck them in. Steve blinked the sleep out of his eyes for long enough to look at Tony's eyelashes with loving eyes. The next moment he opened them again, Tony was rutting against him and moaning, demanding more. And so he did for the next 35 hours.

* * *

 

“Tony! What's going on? Banner called and said you went into heat and you've been holed up in your room ever since! How are you even alive?!” Pepper burst into the kitchen, startling all but Natasha. Tony looked up from his pancakes, then at Steve, who was sitting oddly close to him. The blonde blinked back at him with amused eyes.

“I'm fine Pep.” Tony said, looking at her. Pepper obviously put two and two together, because her eyes widened “oh God.. Tony, really? Of all the.. were you really? You were.. compatible?” she asked, her usually calm, never-shocked-by-Tony demeanor failing her. Tony grinned and Pepper caught a glimpse of Steve's arm finding it's way around Tony's waist, pulling him closer. Tony moved his head slightly, grinning, then nodding. Steve on the other hand, was looking at Tony, who obviously noticed.

“We tried... but weren't compatible, so Pepper and I just stayed friends.” Tony said, reassuring Steve with a curt nod to Pepper, who nodded “we weren't.” she said. “Wait! So you mean that you are aniuman too?” Clint asked, sniffing the air. Pepper smiled softly.

“So is Happy, I used to think there was lots of aniumans when I was younger..” Tony said “there were, but you know, discrimination and such..” Clint said. Tony nodded “I know.” then he turned back to Steve “besides, Pepper is bonded with Happy now.” he said. Steve looked at Pepper with a shocked look before he nodded shortly, finally accepting her. “Geez, you guys are such obvious Alpha's, stop it!” Clint suddenly said. Tony snickered.

“Can't help it can they? I don't really mind, but hey, I got Steve so I'm not gonna complain.” Steve leaned in, pressing his face into the crock of Tony's neck “feelings returned.” he muttered. Then Pepper coughed.

“So, if you were in a heat..” she began. Tony raised an eyebrow “yes? What about it?” he asked. Clint groaned and slammed in forehead into the table while Bruce and Natasha blatantly ignored them. Thor just continued to eat, not really caring about this because it was none of his business.

“What if you get pregnant?” and Tony's jaw actually fell “pregnant?” he asked, then he looked at Bruce, who sighed “Steve's a superhuman, with that in mind, getting pregnant has.. likely.. well, you know..” Bruce moved his hands to somehow get the words across. Tony groaned and Steve buried his face further into Tony's neck, blushing. Even his ears was red.

“I wouldn't mind if there's gonna be some mini soldiers running about in some months, but.. what's it gotta do with everything else?” he asked. Pepper groaned and pushed both hands into her face, rubbing her temples.

“Tony, the press, they'll have a field day if they find out Captain America made Iron Man pregnant and that they aren't even married, have barely been together for a couple of days!” she said. Tony's face fell and Steve suddenly sat up, eyes wide, then he pressed his lips together.

“We're taking that then, as far as I'm concerned and Tony's safety goes, nothing bad is gonna happen.” Steve said and Tony grinned “I'm fine with that.” he said. “wait? Did I hear that right? No argument? Nothing? You two never get along!” Clint said, once again joining.

“So? That never meant we didn't like each other.” Tony barked back and Clint gaped “you two.. are impossible, wait till Fury hears about this.” Tony paled ever so slightly and Steve growled at Clint, who pulled back, suddenly wide eyed and tense. Everyone else, including Thor was suddenly watching Steve and Clint, the latter nodding suddenly “I wouldn't.. even dream of telling Fury, you know that.. it's just, he'll find out, sooner or later..” he said, obviously scrambling to get away from Steve's glare. The blonde nodded.

“Fine, but that's until then..” he muttered. Suddenly Tony stood up, dragging Steve with him.

“Well, let's not take the sorrow before it's here, you, come with me please..” and dragged him away, chuckling at Steve's large, wide eyes and blush.

“God Stark, stop fucking like rabbits!” Clint yelled after them.

“Rabbits don't knot!” Tony yelled back and Clint smacked his head into the table again.

“Oh God..” the others was in a mixture of amusement, annoyance, carefree and clueless. “His a fucking dog or something..” Clint muttered “well, not quite..” Bruce shot in and Clint looked up at him “what? What is he then? No other specie knots except canine!” and Bruce nodded “that is true, but Tony told me he was a mix, it seems that Steve is.. canine.. and bird.” and the room fell silent.

“WHAT?!” came a unified shout from Pepper, Clint and Thor. Natasha didn't seem to care at all.

“Wow..” Clint breathed out. Pepper nodded “wow indeed, that's quite something.” the rest agreed silently.

“So, if he knots, doesn't that.. make the chance of getting Stark pregnant much more?” Clint asked and Bruce nodded “it does, however, the specie's doesn't actually go well together, so we can only hope.” then there was a silence before Clint started laughed.

“He's got a knot! Holy crap!” he suddenly said. Bruce blushed slightly then “I do to..” and Clint gaped at him “woah, yeah, forgot that..” Bruce just smiled “it's okay.” suddenly Tony came back in, shirt half off him and pants undone quite nicely.

“Sorry, forgot the pancakes.” he said, stuffing it all into his mouth and turning to leave.

“Is it big?” and Tony turned to stare at Clint like he was actually growing an extra head.

“What? What is big?” he asked “the knot?” Clint asked. Then Steve was there, dragging Tony out of the room, the latter smirking widely “I have always been a XL queen size.” and laughed at the face Clint made. Steve was hiding his blush by walking away.

“And yes, Clint, knot's usually are big.” “fuck you.” no, Steve does that.” “STARK!” “you deserved that one.” Tony shot back “you did.” Steve agreed “and we're a bit busy, knot or not.” and they left, both grinning like idiots.

Later they got yelled at by Fury and haunted by the press, but with a litter of three running about in nine months, Tony took the embarrassment and the shame like he did everything else, with the middle finger raised and a grin on his face.


End file.
